Residential and commercial solar power has become increasing popular as industry costs have come down and the importance of diversifying away from fossil fuel-based power has increased. Some of this is attributable to reductions in module costs and some is attributable to innovations in mounting hardware, which in turn reduce material costs and labor costs. Other factors, including rising CO2 levels, and increased awareness of climate change are also contributing to the rapid adoption of solar. In order to maintain solar energy's current momentum and for the industry to continue to scale at current rates, additional reductions in cost-per-watt must be achieved relative to other forms of so-called “dirty power.”
Solar systems have relatively few components. The primary ones are the panels, mounting system, inverters, electrical interfaces to existing grid power, and the labor involved installation. Therefore, a reduction in any one of these will have a measurable impact on the cost per watt of solar. Solar mounting systems in particular effect not only hard costs associated with a solar system, but also potentially soft costs such as labor, crew size and installation times.
Traditionally, solar panels have been installed using aluminum or steel rails and mounting brackets. These rails were laid out in a grid pattern over the desired array location and the modules were clamped down or otherwise attached to these rails. While functional, rail-based systems utilize large amounts of material and take a relatively long time to install. Eventually, pioneers in the solar industry, like Jack West of San Rafael, Calif.-based Zep Solar, recognized that the frames of solar panels are sufficiently rigid to support their own weight and withstand wind forces without requiring rails. This led many solar mounting hardware makers and installers to eventually move towards rail-free or so-called direct mount systems. These rail-free systems rely on solar panel mounting brackets that are attached directly to the roof without any rails.
Most modern rail-free systems, and in particular those used on composite shingle roofs, the most prevalent residential roof-type in the United States, rely on flashings. Flashings are flat pieces of sheet metal used to divert rainwater around chimneys, skylights, attic fans and other structures that penetrate a roof surface. Although low-tech in nature, flashings do provide some advantages in solar installations. First, they are universally accepted by building inspectors for protecting roof penetrations from water leakage. Second, because they are relatively large compared to the size of a drill hole, when used in solar installations, they cover up errant drill holes that miss a roof rafter.
These advantages, however, come at a cost. First, flashings are expensive. In solar applications, they are often specially manufactured with stamped features to mate with a particular mounting bracket, they may contain rubber parts, and they require additional installation time, materials and tools. Second, in order to properly install a flashing, existing roofing nails holding down the surrounding shingles need to be cut or removed so that the flashing can be tucked under the up-roof course of shingles. Every roofing nail that is removed to accommodate a flashing is a potential point of ingress for water requiring additional sealing. Third, because of the modifications that must be made to the roof to accommodate a flashing, all flashings and mounting supports have to be installed first. This creates an installation bottleneck because all flashings must be correctly positioned and permanently installed before any solar panels can be placed.
Therefore, there exists a need for a rail-free mounting system that is not dependent on flashings, and that can be installed in-step with the array, without compromising the other benefits conventional rail-free systems.